Production of diolefins



l April 27, 1944s. y

w. R. F.v GUYER PRODUCTION OF DIOLEFINS Filed April 22, 1944 @mmm n @Mmmm rllllllulllh-uDl-ll Ow M my dmmidunjw Srw do nu Nazis@ QF @U21/er latent'ed v Apr. 22,17, 1948 andraiy rRonUo'rroN oF loionrzrnzsv Walter R. F. Guyer, Roselle, N1 J., assigner to Standard l! Development Company, a corporation ot Delaware Application April 22, 1944, Serial No. 532,227

2 Cla.

` 1 The present invention relateslto the production of diolefins, and more particularly it relates to the manufacture of butadiene by the dehydroaiiow plan illustrating a preferred modification genation of amylenes accompanied by the splitting oif of a carbon atom.

A great deal of research has been directed recently toward the production of butadiene, a material which is an important ingredient in the manufacture of synthetic rubber and rubber substitutes. In the normal renery processes, such a catalytic cracking of hydrocarbon oils or steam crackingv of hydrocarbon oils, minor amounts of butadiene are produced. The total amount of butadiene produced in the normal operation is far below that necessary to satisfy the present requirements for this very important material. There have been developed processes for produclng butadiene from butane which is available in relatively large quantities as a result of petroleum refinery operations, as Well as from natural gas'sources, namely, from the s'o-called r fleldbutane sources. The butane is ordinarily dehydrogenated to form butenes under one set of conditions and using special catalyst and thereafter the butenes are dehydrogenatedpreferablyr using another type of catalyst to form the butadiene. Also, butenes are formed in substantial quantities in the normal reilnery practice, particularly during catalytic cracking or steam cracking of gas oil, and these butenes may be dehydrogenated. An excellent catalyst for the dehydrogenation of butenes to form butadiene consists of iron oxide supported on magnesium oxide, promoted with potassium oxide and sta' bilized with copper oxide.

My present invention relates to producing butadiene from another source, namely, from vthe amylenes or pentenes which are available in substantial quantity4 as a result of refining hydro,-

carbon oils. In brief compass, my. invention involves treating a mixture of amylenes at elevated temperature in the presence of a suitable catalyst whereby I produce butadiene in substantial yields as a butadiene-rich C4 stream, in addition to the pentadienes.

The main object of my present invention is to provide means for producing butadiene in an expeditious vand economical manner. i

In the accompanying drawing, I have indicated top of a reactor l0.

of my invention.

Referringin detail to the drawing, a mixture of amylenes is withdrawn from storage I through s line 2, thence passed through al fired coil 4 and thence passed by an extension of line 2 into the Meanwhile steam from some source is introduced into the system through line 3 and superheated in a superlieate` 5, and theref after discharged into'the reactor l0.. A' suitable catalyst is disposed in said reactor. This catalyst may be manganese dioxide, chromium oxide, iron oxide, cobalt oxide,'and/or nickel oxide supported on a base such a; magnesium oxide, zinc oxide, or barium oxide, with an added alkali metal promoter such as KzO. Oxides such as CuO, A1203, ThOz, etc., may be present as stabilizers.. The catalyst itself .is in the physical form of pills,

pellets, granules, and the like, disposed on a screen or other foraminous member I5. A temperature of from 1100-1400 F. is maintained in the ,reaction zone during the reaction. This temperature is acquiredy by preheating the amylenes and the steam and mixing them in'suitable proportions to obtain the desired temperature. The ratio of steam to amylene feed entering the reactor is from 5-40 volumes of steam per volume of amylene, and the total gas pressure within the reaction zone is of the order of l1 atmosphere. The partial pressure of the amylenes will be merely a fraction of an atmosphere. This condition is desirable because it `favors the demethanation and'dehydrogenation reactions and because the nascent butadiene or other dioleins formed tend to polymerize', and the reduced` pressure counteracts this latter tendency.

The reaction products are withdrawn through line 20 and are passed through a Waste heatboiler f 22 where they are-cooled. Preferably, however,

4before withdrawing them from the reaction zone with water immediately as they issue from the bed of catalyst to prevent polymerization, degrav v.dation and other undesirable reactions causing losses in yields. The gases are cooled by the quenching water injected through line 2l to a temperature of, say, 9001000 F. and are further cooled in the waste heat boiler 22 to a temperature of, say, 500 F. The products are withdrawn from waste heat boiler 22 through line 24 and usually quenched with oil in an oil quenching instance, a good catalyst is one which contains the followingingredients in parts by weight:

l Paris by weight. l Roughly two parts pentene-2, onaiart trlmethylethylene. l Volumes oi hydrocarbon vapor l Volumes of steam per volume of hydrocarbon.

l The C; dioleiin was analyzed for by maleic anhydride reagent.

- with. Suilice it to say it may be purified in known manner (by the use of selective solvents, etc.)

and recovered in a commercially pure state.

Having generally described above an operation in which a preferred 4modification of my invention may be carried into effect, I wish to point out that I purposely omitted a number of conventional expedients that may be employed in order to aid or improve the process from en zone 26. the oil such as cold naphtha being in llgs 20 Jected into zone 26 through line 28 and with- 5 Cuo 5 drawn through line 30. In oil quenching zone m0 5 20 the product is cooled to about 220-400" F., y l namely above the condensation temperature of This catalyst has the advantage that it'may steam, because it is desirable to prevent co-con- .be regenerated by steam. In other WOrdS. a Dredensationof steam and tarry material, since 1o ferred way to operate my process iS t0 conduct emulsiflcation difficulties would ensue, the water the Operation in two-heur cycles. the rst hour tending bo be polluted with tar and polymers, being devoted to feeding a mixture of steam and hence'causiug a, disposal problem. Accordingly, amylenes to the reaction zone to form a desired the vapors withdrawn from quenching zone 20 butadiene and the next hour the feed of amylene through line 32 contain the bulk of the steam 15 is discontinued and the catalyst is merely treatwhich was originally added or mixed with the ed with steam. It is necessary to regenerate reactant, and the steam is condensed in a coil the catalyst periodically because the productive 34,. thereafter the water and product are -withphase 0f the Operation dOcS rcSUJt in the 'deposi- Vdrawn through line 36 and discharged into a tion of tarry materials on the catalyst. To give water separator 38 from which the water may 2o speciflc examples illustrating my invention, I. be withdrawn in relatively clean condition set forth below the conditions and results of through line I0, while the product is withdrawn experiments which have been made. overhead from the separator 38 through line 42 In these runs the C5 olefins, pentene-2 and and ydischarged into a butadiene purification sys-` trimethylethylene, and a mixed pentenes feedtem which I have indicated as 50. It will not be 25 stock (amylene) have been dehydrogenated over necessary to describe in detail the method of a catalyst of the composition set forth immepurifying butadiene separated from' unchanged diately above. The conditions and results are amylenes and other materials associated there- 1 set forth in the table.

Tame` Comparison of behavior oi' various C; oleiins when the arotpassed over a dehydrogenation catalyst of the composition: 78.5 Mg0-20 F6101..

v 6 CuO-5 0 1 in the presence of steam d11uent.]

Fdmck Pini... Tiit'" Pemba-2 l. Feedrate, viv/Hr 8 485 476 486 498 508 steam Dilution Ratio* 5.4/1 1.1/1 e. 9/1 7.6/1 13.7/1 Temperature, F 1,210 1,200 1,150 1,200 1,200 Conversion, Mol Per cent 46. 7 2. 4 4. 7 2. 2 4. 6 Yield of Pentadlena Mol Per cent, on Feed.. 18. 0 27. 7 7. 6 11-.3 l0. 8 Yield of Butadiene, Mol Per cent, on Feed. 8. 0 0. 9 8. 7 14. 1 13. 8 Yield of Butenes, Mol Per cent, on Feed 6.3 4.4 2.2 4.0 3,4 Yield ol Pentadiene, Mol Per cent, on reacted feed 38. 5 65. 5 30. 7 26. 8 24. 2 Yield o! Butadiene, Mol Ier cent, on reacted feed. 17. lv 2. 1 35. 2 33. 4 31. 0 Dioleiin Concentration in C1 Cut, Mol Per cent 25. 2 32. 5 9.2 16.2 16.4 Tertiary Olen Conc. in C; Cut, Mol Per cent-- 59. l 18. 5 28.7 12.0 Dioleiin in C4 Cut, Mol Per cent 55. 6 17.0 78. 5 78.4 81 Coke, Wt. Per cent as C, on Feed 2. 5 1. 5 2.5 1.6 1.9 CO-i-CO. Wt. Per cent as C, on Feed 4.5 4. l 1.4- 4.6 8. 2

culated at standard conditions) per volume of catalyst per hour.

These data indicate that while trimethylethylene is dehydrogenated selectively to C5 diolen (largely isoprene), pentene-,Z (the straight .tration facilitates the purication of the butadiene.

The catalyst which I may use is preferably one containing iron oxide, magnesiumIoxide, copper and potassium oxide. These components may be used within the following range of proportions:

Component: er cent by weight MgO 50-95 FezOa 3-49 wo, KzCOa, KOH 0.5-10

CuO (stabilizer) 0.5-20

Numerous modications of my invention may be made'by those who are familiar with this art. For example, instead of using amylenes I may use hexenes, or hexenes admixed with pentenes, and the products produced will include not only butadiene but also other diolens, such as pentadienes and hexadienes.

In the drawing I have shown a stationary bed of catalyst in reactor l0. It is to be understood that I may employ a uidized catalyst, i. e. the steam and reactants may flow into the bottom of the reactor containing powdered catalyst under flow conditions such that the catalyst is maintained in the form of a dense phase suspension. In this type of operation the catalyst may be withdrawn periodically and regenerated in a separate vessel and returnedl to the reaction zone thus maintaining continuity of operation. Also a further modiiication of my invention involves using catalyst in the form o1' microspheres.

What is claimed is:

1. The method of selectively producing butadiene and pentadiene in controlled proportions from pentenes, which comprises charging a mixture of steam with a, pentene feed having a controlled proportion of trlmethylethylene and of a straight-chain pentene to a reaction zone in which the mixture is contacted with an active dehydrogenation catalyst selected from the class consisting of manganese oxide, chromium oxide, iron oxide, cobalt oxide and nickel oxide associated with a base 'from the class consisting of magnesium oxide, zinc oxide, and barium oxide, together with an alkaline metal compound having lbasic properties and a stabilizing oxide, maintaining the temperature in the reaction zone at essentially between 1100 and 1400 F., obtaining principally pentadiene from the trimethylethylene in the feed and butadiene from the straightchain pentene in the feed, the diolefln product in preponderance being determined by the controlled proportion of the'trimethylethyiene and of straight-chain pentene in the feed, said pentenes being reacted at the same temperature in the reaction zone.

2. The method of selectively producing butadiene and pentadiene in controlled proportions from pentenes, which comprises charging a mixture oi.' steam with a pentene feed having a con-'- trolled proportion of trimethylethyene and of pentene-2 to a reaction zone in which the mixture is contacted with an active dehydrogenation catalyst selected from the class consisting of manganese oxide, chromium oxide, iron oxide, cobalt oxide and nickel oxide associated with a baseA zone.

WALTER R. F. GUYER.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,986,241 Wulf! et al Jan. 1, 1935 2,178,584 Grosse Nov'. 7, 1939 2,178,602 Morrell et al Nov. 7, 1939 2,307,240 Ruthrun Jan. 5, 1943 2,367,623 Schulze et al. Jan. 16, 1945 2,876,191 Roetheli et al. May 15, 1945 2,391,158 Hepp Dec. 8, 1945 2,395,875 Kearby Mar. 5, 1946v Y 2,396,416 Frey Mar. i12, 1946 OTHER REFERENCES Michailoy et` al., Comptes Rendus Doklady de 3.4112325 des Scl. de l'URSS, 1936, vol. III (XII) No. 

